Field of Invention
The present invention relates to air-conditioning, and more particularly to a air-conditioning unit with hybrid cooling.
Description of Related Arts
Chlorodifluoromethane (R22) is a type of low temperature refrigerant which can obtain a refrigerant temperature of −80° C. R22 is a colorless and almost odorless gas at room temperature and is non-flammable, non-explosive and non-corrosive. Both the chemical stability and thermos-stability of R22 is very high. Particularly, in the absence of water moisture, no reaction with general metal will occur below 200° C. When water does exist, only reaction with a base will occur slowly. Though cleavage will occur under high temperature, it is still a safe refrigerant.
Air-conditioning unit refers to a device which utilizes refrigerant such as R22 to produce cold water at 7-12° C. by heat exchange through the work done by a compressor to provide the cold water to the air-conditioned box at the terminal end, and is classified into two main categories, which are air-cooled and water-cooled.
At present, the air-conditioning device which is used by most users in the market is the air-conditioning unit which employs a compressor and a refrigerant system. The energy efficiency ratio of this type of air-conditioning unit is about 3.0. Since R22 is the most common refrigerant being used, the ozone depletion index is 0.05 and the global warming index is 0.34.
At present, some types of air-conditioning device which utilize water-cooled arrangement also appear in the market. For example, Chinese patent CN01270637.X disclosed a water-curtain fan air-conditioning device and CN99220698.7 disclosed an energy-saving water-cooled air-conditioning device. The majority of this type of conventional water-cooled air-conditioning are composed of water curtain, fan, water supply system and related parts. This type of water-cooled air-conditioning device has a very small temperature difference between the air inlet and outlet, which is usually only about 5˜8° C., and the outlet humidity is as high as 95% and the output air always carries water droplets. At present, though this type of water-cooled air-conditioning device can achieve the object of energy-saving, the effect is not satisfactory and further researches and improvements are needed.